Coal pulverizer



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COAL PpLvERIzER Filed Dec. 19. 1923 4 Sheets-Sheet 1 INVENTOR.

@J @Mam 4 Sheets-Sheet 2 A. A. wscKLANp COAL PULVERIZER Filed Dec. 19, 1923 May 1m 1927.

INVENTOR.

y May 10,1927. ,62s,294

A. A. WICKLAND COAL PULVERIZER Filed Dec. 19, 1923 4 Sheets-Sheet 3 um I una I N VEN TOR.

QQ l l j May 10,1927. A. A. WICKLAND COAL PULVERIZER Filed Deo. 19. 1923 INVEN TOR.

W 4 MM Patented May 10, 1927.

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1,628,294 PATENT oFFlcE. A

ALGOT A. WICKLAND, OF CHICAGO, ILLINOIS.

- COAL rULvEnIzER.

' Application filed December 19, 1923. Serial No. 681,455.

My invention relates to-improvements incoal pulverizers, and has for its objects the production of a device of the kind described, wherein'the coal is elevated to the machine from a hopper or other suitable source of supply, separating the metals and other foreign substances therefrom and removing a Aport-ion of the moisture content during such elevating of the fuel.

Other objects of my invention are to provide a machine of the kind described which shall be of minimum size, .large capacity, simple and substantially constructed, and wherein the pulverizer is adapted to be installed and operated in close proximity to the furnace in which the pulverized coal discharged from the pulverizer` is to be consumed.

Other objects of my invention are to provide for the ready removalof the Wear elements and to compensate forthe Wear of these partsso that the cost of renewal and maintenance may be reduced to a minimum.

Referring more particularly to the drawings in which like reference characters indicate like or corresponding parts,

Fig. 1 is a longitudinal cross-section View through the pulverizer.

Fig. 2 is a rear elevation thereof.

Fig. 3 is a fragmentary cross-section through the coal feeding trough.

Fig. 4 is an end elevation of the pulverizer shown in connection with the furnace and Sourceof coal supply.

Fig. 5 is a cross sectional view of .the pulverizer casin'gor housing with the 1'0- tary impact discs removed.

Fig. 6 is an elevation of the rotary impact disc assembly, taken from one end.

Fig. 7 is a similar view, taken from the other end. l

Fig. 8 1s an enlarged fragmentary side Y elevation of the pulverizer rods and discs.

Fig. 9 is a top plan view of the parts shown in Fig. 4; and

Fig. 10 is a diagrammatic view of the gears for actuating-the rotary valve.

' Referring more particularly to the drawings, 1 indicates a furnace or other similar structure that is to receive the-pulvcrized fuel that is to be burned therein; the/same having an inlet 2. A pulverizer 3' is arranged at any suitable point, preferably in -close proximity to the furnace as shown :more particularly in Figs. 4 and 9. A' hopper 4-may be located at any suitable place as-shoWn in Fig. 4, the same in the present embodiment being shown as a floor hopper.

The pulverizer itself comprises a supporting frame or base casting 5, of any suitable size and shape, having a. fuel intake 6 at its upper end and a discharge outlet 7, also preferably located adjacent the upper end thereof; the latter leading to the furnace intake 2 by means of a conduit 8. The outer end of the chamber housing or base casting has a removable cover 9 there' for so as to provide easy access to the parts within the chamber when the occasion arises. t

Arranged Within"the chamber 10 of the housing are a plurality of rings 11 of progressively varying diameters, these rings being concentric and arranged longitudinally in a series. A web 1 2 may be provided within the chamber to secure the rings 1'1 thereto; bolts 13 being used for removably holding the rings in place. The inner peripheries of the rings and one of their sidel faces are roughened or corrugated as at 14 and 15, the former indicating the peripheral corrugations and the latter the end corrugations. The largest ring need not have the end face corrugations, if so desired. j

The rotary shaft 16, driven by any suitable source of power, is arranged to extend into the chamber 10, the free end of the shaft being adjacent the open end of the housing so that when the cover plate 91is A removed, access may be had thereto.

17 to 21 inclusive, there being 5 discs in the construction shown, although the exact number of discs is optional and dependent Yupon the number of stages of pulverizing desired.

Extending longitudinally through the discs, the latter being removably keyed to the shaft, are. a plurality ofseries of pins 22, there being a series of pins foreach of the rings 11. Each series of pins is arranged annularly and extends parallel to and closely adjacent.' the inner corrugated face of its co=operating ring 11, as shown more particularly in Fig. 1.

The pins are rotatablyinounted through apertures in the discs and are secured in placeby means of nuts 23 or the'like on rthe outermost disc 21. It will be apparent that the pins may" be partially rotated for adjustment after loosening the nuts 23, and then tightening the same.

The pins of the adjacent series are of ditferent lengths, the pins closest the shaft 16 and coacting with the smallest ring being the longest. The outermost disc 2l is spaced from the cover plate 9 and has vanes or blades 24 at its periphery and projecting into said space so as to set up air currents when the shaft is revolved. Additional blades 25 may be provided between the end discs 20 and 2l at their periphery.

The Jfuel is delivered into the chamber l0 through the inlet 6 in a manner to be hercinat'ter described, the same entering the spaces between the grinding rings and the rotating pins and becoming pulverized bcore it is discharged upwardly throughout outlet 7.

The corrugations on the grinding rings serve to retard the flow of the fuel past the grinding elements and insure that the grinding willibe evenly and efficiently done. As the grinding surfaces of the pins 22 become worn they may be partially rotated and locked in their new position ot' adjustment so as to compensate for wear, thus providing a new grinding or impact surface as fast as the old surface becomes worn. It is to be understood that the pins 22 may be of any cross-sectional shape, as for instance circular, triangular, hexagonal, or the like.

lVhen the grinding pins become worn on all Sides adjacent their co-operating grinding rings, they may be removed and sliertened or cut off for insertion into the adjacent shorter series of pins. That is, when the pins of the lowest series, which in this case are the longest pins, become worn at their ends, they are cut ottn to the length of the next shorter pins and are inserted or sub` stituted for the latter. In practice the wear will be substantially uniform on all pins so that when the replacing is done the pins are merely shortened and each moved" up to take the place of the next shorterpins.

The cover plate 9 is dished out or enlarged to provide a chamber 26 substantially concentric with the discs adjacent their centers, and a rib or flange 27 is provided on the cover plate to extend laterally inwardly to closely adjacent, but not in contact with, the end disc 21. c

A conduit 28 leads from the chamber 26 to a separator 29 as shown more particu-` larly in Fig. l. At this point it may be mentioned that the end disc 2l has one or more openings 30 therethrough adjacent its center as shown in Fig. 7 so that when the shaft 16 is rotating, the fans 24 and 25 will cause a suction inwardly `ot the vchamber 26 through the apertures 30 and outwardly ot the discharge outlet 7, thus creating a suction in the separator 29.

The chamber 26 may be considered as a high suction chamber, while the chamber formed between the rib 27 and the outer periphery of the disc 2l will be a low suction chamber.

VViclrets 3l and 32 may be provided in the cover plate 9 to control the admission of atmospheric air to the high suction and low suction chambers and regulate the suctions therein.

In operation the coal discharged through the inlet 6 will tall into the chamber l() and, due to the suction therein and to the centrifugal torce ot the pins, will be drawn through the cti-operating grinding or impact surfaces in series or in successive stages, and thence be discharged through the opening 7.

A slowly driven rotary valve 33 is arranged in an extension chamber 35 beyond the discharge outlet 7, so that the heavier particles of pulverized coal may drop or collect therein. The underside ot the rotary valve. communicates with the intake side of the chamber 10 so that as the valve is revolved the coal therein will drop into said chamber and be again fed to the grinding elements. Any suitable means may be provided or driving the valve 33, as for instance the gears 34 shown in Fig. 10.

The chamber 35 into which the pulverized fuel is discharged before iti admission to the conduit 8, is under considerable static pressure due to the action of the grinding elements, and the fan blades, and therefore the rotary valve 33 forms an etlective seal between this chamber and the coal feeding chamber 10 which is under a partial vacuum. A hinged battle plate 36 may be arranged in the chamber 35 to retard the flow and circulation of air set up by action of the tan blades, this bailie plate being adjustable from the outside of the casing.

The separator 29 discharges into a trough 37, past a counterweighted gate or valve 38, hinged at 39 and counterweighted as at 40. Then a sufficient amount of coal has collected above the gate 38 the weight of said coal will open same and permit the coal to fall into trough 37.

An overflow pipe 4l is provided leading from the separator to return the surplus 'coal to hopper 4. The pipe 41 may be provided with a hinged dalnper 42 therein -to prevent atmospheric air entering the separator, the weight of the coal opening the damper.

In the trough 37 is mounted a pusher or scraper 4? on a rod 44, said rod being given a reciprocating movement by means oi' drive mechanism 45 shown in Figs. l and 2. Adjusting means 46 may be provided to vary the stroke ot the pusher and so control the amount of coal discharged troni the trough at each reciprocation thereof.

The coal in the hopper 4 is discharged into a trough 47 having a screw conveyor 48 or other suitable device for the purpose. The

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49 and a suction pipe 50 communicates withsaid discharge end of the trough and extends upwardly therefrom to the separator f 29 which it enters adjacent the upper end and tangentially thereof. (See Figs. l1 and 2.) f

A gate 51 is hinged to the intake end of the suction pipe 50. The suction within the separator induced by the suction through the conduit 28 leading from the high suction chamber 26 is suiiicient to draw the coal from the trough 47 upwardly through the conduit 50, discharging lit into the separa- The burner at the inlet to the furnace may be of any suitable construction and does not forma part of this invention.

In order toY supply auxiliary air tothe furnace to support combustion therein said air may be admitted through pipe 55, the

mixture of pulverized fuel and air being carried from the extension chamber' 35 by means of the conduit 8. As has been hereinbefore described, the coal is fed into the hopper 4, carried upwardly through the pipe 50, discharged into the chamber. 10 of the pulverizer through the inlet 6, where it is 'engaged by the rotating pins. The action of the grinding pins throws the coal outwardly against the grinding rings and pulverizes it in a series of stages after which it is di' charged upwardly into the extension chamber 35 and passes through the conduit 8 into the burner.

The ratio betweenthe fuel andair may be varied as desired, but in order to secure the best results at the burner this ratio must be kept constant.

It is to be noted that the pins at the first stage of grinding are spaced a farther distance from the co-operating surface ofthe stationary grinding ringthan the next set ofpins, the next set of pins is spaced closer to the co-operating grinding surfaces of its coacting ring than the pins of the next stage, and so on, because as the fuel passes through the successive stages of grinding it is of progressively increasing fineness.

What I claim as new and desire to secure vby Letters Patent is:

1. In a device of the kind described and in combination a pulverizer comprising a housing having an inlet and outlet for the material, a rotary driven shaft therein, a plurality of series of pins driven by said shaft, and grinding ringsfone spaced about each series of pins, the said rings and the coi operating ends of said series of pins being arranged in stepped relation.

2. In a device of 'the' kind described, the combination of a pulverizer comprising a housing provided with an inlet and outlet, a drive shaft therein, a plurality of series of pins operatively connected to said shaft'and driven thereby, and an impact ring spaced ingadacent to the ends of the pins of the next a jacent series of pins;

3. In a deviceof the kind Adescribed comprising a pulverizer housing having an inlet and outlet, a rotary drive shaft therein, a plurality of s eries of annularly arranged pins driven by saidsliaft, impact rings arranged in said housing, each surrounding one series of said pins, said rings and the cooperating ends of said pins being arranged in stepped relation, certain of said rings having an edge adjacent to the ends of the pinsv of the next seriesf" 4. 'In a device of the kind described comprising a pulverizer housing having an inlet for the material and an outlet for the /pulverized material, a drivel shaft therein,

said shaft and driven thereby, aplurality.

of se'ries of pins extending parallel to said shaft, each series arranged annularly and the adjacent series beingof progressively lvarying lengths, stationary `grinding rings co-operable with said annular series and spaced concentrically therefrom and means for. adjusting each of the pins individually to compensate for the grinding wear thereof.

6. In a device ofthe kind described, comprising a pulverized housing having an inlet and an outlet, a rotary drive shaft therein, a plurality of annularly arranged series oi pins driven Vby said shaft, a series of corrugated impact rings, arrangcd in stepped relation and spaced from the series of pins. respectively, and arranged to coact therewith.

7. A pulverizer comprising a housing having an inlet and an outlet, a drive shaft, a plurality of series of annularly arranged pins driven by said shaft, a series of grinding rings spaced from each series of pins, said rings corrugated about their inn-er peripheries and at their outer faces, the adjacent series of pins being of progressively varying lengths, and means for-inducing sura plurality of seriesof pins arranged annu larly through said discs, the adjacent series being of progressively varying lengths, all of said pms removably secured to one of said discs, aA series of grinding rings each surrounding a series of pins, and a movable cover plate on said housing whereby access may be had to the pins and said shaft.

9. A piilverizerhousing having a removable end cover, discs in said `housing arranged substantially parallel to said cover, grinding elements carried by said discs, fan members carried on said grinding discs, a separator to receive a supply of coal which discharges into said pulverizer housing, a conduit open: ing into said separator at one end, and leading through said cover plate at the 'other end, and a continuous rib extending inwardly from said cover plate to closely adjacent the Vgrinding discs to form a. suction chamber therewith.

10. In a device of the kind described and in combination, a pulverizer housing having a. removable cover plate at one end, a separator communicating with said housing for admitting material thereinto, an outlet leading from said housing, discs within lsaid pulverlzer, a drive shaft carrying said discs, grinding elements mounted on said discs. a rib on said cover plate and extending inwardly to closely adjacent the end dse, said last mentioned disc having apertures therethrough, fan blades carried by said discs adjacent the periphery thereof to induce flow through said outlet, and a conduit between said separator and cover plate, said conduit entering said cover plate radially inwardly of said `rib.

11. In a device of the class described, a housing, a pulverizer in said housing, a separator chamber above said housing, an outlet for the pulverized material joining said housing to said chamber, meansl for creating a blast of air through said outlet. a. conduit extending from said chamber for the passage of finer pulverized particles, a rotary valve in the bottom of said chamber for returning the coarser particles to the intake side ot said pulverizer, and an adjustable bafiie in M said outlet for controlling the velocity of the air current therethrough and the coarse- `ness'of the material passing through said pulverizer housing, a drive shaft therein, a r

plurality of discs spaced longitudinally otv said shaft and driven thereby, a plurality of series ot beaters annularly arranged and carried by said discs, impact rings surrounding the operative ends of thebeaters of said series, respectiyely, the said rings and beaters being arranged in stepped relation, the said discs being arranged to terminate adjacent to the inner sides of said rings, respectively. 14. In a device of the class described, a housing, a pulverizer in said housing, a material receiving chamber, a passageway joining said chamber to said housing, ay

source of supply of' material to be ulverized below said chamber, a conduit joining said chamber to the said source, and means included in said pulverizer adapted to create a suction through said passageway whereby the said material is raised by Suction into said chamber. j

In testimony whereof, I have hereunto signed my name.

ALGoT A. WICKLAND. 

